Heteroclite

Webster's Dictionary of the English Language

·adj Deviating from ordinary forms or rules; irregular; anomalous; abnormal.

II. Heteroclite ·noun Any thing or person deviating from the common rule, or from common forms.

III. Heteroclite ·noun A word which is irregular or anomalous either in declension or conjugation, or which deviates from ordinary forms of inflection in words of a like kind; especially, a noun which is irregular in declension.